1. Field Of The Invention
The invention relates to a process and an apparatus for the production and further processing of strands for Bowden cables from a plurality of wires stranded together by twisting.
2. Background Of The Art
It is known to use Bowden cables for the transmission of tensile and compressive forces. Bowden cables comprise a flexible pull wire formed by strands prepared by twisting, a flexible tube surrounding the pull wire and sheathing formed of wire fabric, wire mesh or tightly wound wire spirals. The known Bowden cables are found to be highly satisfactory in applications involving the transmission of high tensile forces or in some case even compressive forces. However, they could not be used heretofore in applications requiring great accuracy and consistency of control. The essential cause of this condition is the fact that the strands, elongate elastically in themselves, i.e. without an elastic or even plastic deformation of the individual wires of the strands, under the effect of the control forces to be transmitted, and subsequently contract upon their release. On the one hand, the measure of the elastic elongation and contraction is undetermined and varies from cycle to cycle, and on the other hand, changes in length remaining in superposition may occur. In a measuring apparatus or control segment this phenomena leads to a permanent change in the zero point of the measuring apparatus or the control element. This is true of strands from both single wires and composite strands.